Elastic yarn and method of making it



- Oct. 4, 1938. T. LfsHEPI-IERD v ELASTIC YARN AND METHOD DEMAKING IT File d Feb. 25, 19s! Q QQZ Patented Oct. 4, 1938 UNETED STATES PATENT OFFICE Application February 23,- 1937, Serial No. 127,257

In Great Britain February 28, 1936 9 Claims. iCl. 117-57) This invention relates to rubber processes and products in which rubber is manufactured in thread or filament form and also to processes and products involved in or resulting in fabrics such as woven, knitted or lace work, formed from or incorporating such threads or filaments.

The word thread-will be hereinafter used result, the core cannot later retract to its more to cover thread or filament.

Rubber may be manufactured in such form according to one method by extruding latex or other coagulable dispersions of rubber or rubberlike materials with or without other ingredients such as vulcanizers, accelerators, reinforcing fillers, anti-oxidants and stabilizers.

In British patent specifications Nos. 447,972, 448,098, 449,314 and 449,462 and British patent applications Nos. 10,448/35, 18,200/35 and 30,-

481/35,--I describe processes in which there is mixed with the latex or latex mixture for extrusion purposes, or with a liquid coagulant for the latex, when such is used or in which there is otherwise intimately mixed with therubber, various extensibility-reducing agents, such as glue, gelatine and similar proteins, casein, albumen, natural and synthetic resins and gums which are water soluble, cellulose esters and ethers (e. g. methyl cellulose), and inorganic (e. g. sodium silicate) or organic substances (e. g.

sugar) which dissolve in water to give solutions lation It is not intended to be implied that all such substances will be advantageous from every aspect, for example, as is well known, copper saltsgreatly accelerate the rate of perishing of 35 rubber from the Hevea braziliensis, so that in selecting the extensibility-reducing agent regard must be had to the possibility of such other e fiects. When the latex mixture is extruded or otherwise formed into thread by processes m 40 cluding coagulating the rubber, and is dried, a relatively inextensible thread is produced, which may be woven or otherwise manipulated without the dificulties associated with extensible threads.

Relatively inextensible threads can also be made according to British patent application No. 30,-

481/35, according to which an extensibility-reducing agent may be incorporated with rubber by masticating the extensibility-reducing agent with rubber in a compounding mill, or mixing it with a rubber dough in a colloid mill, the threads being formed as desired, for instance by cutting a sheet of the rubber or the like mixture.

Elastic yarns not of this relatively inextensible character when covered with fine cotton or silk spun thread suffer from serious defects, the principal ones being:

(1) In the winding process the cores have to be subjected to avery severe stretch, in some instances approaching the figure of 3'70 per cent., 5 for otherwise the winding fiyers, which cover the core at high speed, would be ineffective. As a or less normal length because to a great extent the textile covering prevents it. There is also 10 a tendency for the tension to be not or not quite even. When incorporated into fabric, the weaving brings out this uneven tension and the cloth is puckered in parts, a fault which cannot be permanently remedied. 15

(2) The textile winding has an insufficient grip on the core and slips and this shows itself when the covered core is subjected either in the weaving, knitting, or lacing machine or in the fabric to tension, a tension which it is the normal function of the thread or fabric to resist. The textile covering should extend and contract with the core but owing to the aforementioned. slip this does not always happen and it is found that I in some places the textile winding or covering 5 becomes displaced in its relation to the core. In such places the fabric again shows a permanent pucker.

(3) The cost of cotton or silk covering is very high, as only very fine spun yarns can be utilized. The high cost of covering material brings the price of the complete fabric or article very often to a prohibitive level, and the cheaper artificial silk filaments cannot be used as they are considered too slippery. r

The object of the invention is to provide processes for the manufacture of improved yarns, and another object of the invention is to overcome the above disadvantages.

According to the present invention a relatively inextensible thread, as before referred to, is used, and enablessatisfactory winding to take place ata much lower stretch, whilst the presence of extensibility-reducing agent modifies the surface of the thread by rendering the surface plastic so that the possibility of slipping is much reduced,

' both in the case of textile threads and-of artificial a core thread a and a helically wound'covering thread I), the latter being shown as if removed manent grooves o.

By the employment of the thread of the characterreferred to, the winding operation is facilitated in that the requisite conditions for winding can be attained with a stretch of per cent. or

. loosely. The tightness which is required will vary with different cases but no tightness above that which is normal with threads not of the character referred to is generally necessary for obtaining the advantages to a good degree.

The braiding or winding is applied by the usual braiding or winding machines.

. silk covered elastic thread into other materials,-

covering, which leaves it, owing The subsequent removal of the extensibilityreduoing agent allows my core to take on a more pronounced and deeper groove for the winding to rest in and any traces of extensibility-reducing agent which may remain in my core have the action of still more firmly anchoring the winding to the core.

The grooves are slightly more pronounced when the core is wound in a non-vulcanized condition but the grooving also takes place when winding a Vulcanized core.

If, owing to rough handling or accidents, the textile covering becomes damaged or broken, it

may therefore be preventedfrom unwinding or.

becoming separated from the core; it may be arranged thatsuch damage can hardly be detected with the naked eye, when the nature of the core is such that the Winding will in the dyeing process have assumed the same shade as the rubber core underneath.

It is now possible to utilize for winding or lacing material even a filament hitherto considered slippery, such as artificial silk as made from viscose, cellulose acetate, cuprammonium and other materials. This filament need not be spun from staple fibre (although it may be if desired) as is the case with cotton or real silk from fibres but may be extruded. I may use such filaments for winding singly or in multiples and these multiples may either be in a twisted condition or lie parallel. Apart from reducing the cost of the covering material considerably, this artificial silk winding renders it possible to weave or knit or lace a multitude of new fabrics heretofore unknown and I can now produce elastic fabrics and articles with a new pleasing and beautiful appearance and new efiects can be obtained by careful pre-selected incorporation of the artificial producing either uniformly dyed finished fabrics or cross-dyed fabrics.

The relatively inextensible thread may be caused to hold itself extended during the application of the covering. For instance, when gela- .tine is the extensibility-reducing agent, the

thread maybe wound'after the core has been given under steam a predetermined amount of stretch, varying as desired from 1 per cent. to as much as 600 per cent; or more and dried before to its nature, in this stretched condition. 7

The covering with textile matter may also'be applied to the core when it is .in a non-, semi-,

I or fully vulcanized condition.

After theappli'cationof heat, steam, or boiling fiuids, when they are applied for getting rid of the extensibility-reducing agent, the covered core I from the lefthand side of the figure to show perwill then try' to assume its old shorter prestretched shape, but it is to a large extent prevented from doing so by the surrounding textile covering.

However, as the stretch may be pro-determined, the subsequent tension set up in the rubber core by the covering can bearranged to be even and in theweaving, knitting or lacing no puckeringtakes place.

The invention may be used in conjunction with the processes described or' claimed in'British specifications Nos. 423,997, 440,256, 441,002,

443,284, 443,914, 447,972, 448,098 and 449,462 and British application No. 5,085/36.

If desired in addition to the textile coverings hitherto referred to a filament of gelatine or of other soluble substance, may be app ied over the or the like instead of a filament may be used over I the textile covering.

A gelatine or like coating may be applied to the textile or artificial silk covering by passing the covered yarn through a solution of gelatine and allowing the coating to harden or set.

Reference is also made in a preceding paragraph to British specification No. 449,462,- in which it is envisaged to render glue or gelatine' insoluble by meansof formaldehyde when it is used as an extensibility-reducing agent, and after the thread has been formed. The. same process, which results in a thread of permanently reduced extensibility, may be used inconjunctionwith'the present, invention, as well as analogous processes whereby other extensibility-reducing agents may be rendered insoluble in water.

I claim:

1. A method of manufacturing a ya rn which consists in incorporatingin a normally elastic core thread a quantity of extensibility reducing agent sufficient to produce a relatively inextensible and plastic thread, and embedding a textile winding in said thread to form permanent grooves therein whereby slipping of the textile winding is prevented.

2. A method of manufacturing a yarn which consists in incorporating in a normally elastic core thread a quantity of extensibility reducing agent sufficient to produce a relatively inextensible and plastic thread, stretching the thread while moist, drying the stretched thread and emconsists in incorporating in a normally elasticcore thread a quantity of extensibility reducing agent sufllcient to produce a relatively inextensible and plastic thread, embedding a textile winding in said thread. to form permanent grooves therein, and covering the said textile winding with a'soluble filament. 4. A method of manufacturing a yarn which consists in incorporating in a normally elastic core thread a quantity of extensibility reducing agent suflicient to produce a relatively-inextensible and plastic thread, embedding a textile winding in said thread to form permanent grooves therein, covering the said textile winding with gelatine.

5. A method of manufacturing a fabric which consists in incorporating in a normally elastic core thread a quantity of extensibility reducing agent sufficient to produce a relatively inextensible and-plastic thread, embedding a textile'winding in said thread to form permanent grooves therein whereby slipping of the textile winding is prevented, incorporating said thread into a fabric, and removing the extensibility reducing agent from the fabric.

6. A method of manufacturing a yarn which consists in incorporating in a normally elastic core thread a quantity of extensibility reducing agent suflicient to produce a relatively inextensible and plastic thread, embedding a textile wind-.

ing in said thread to form permanent grooves therein whereby slipping of the textile winding is prevented and treating the thread to render the extensibility reducing agent partially insoluble to control the ultimate elasticity thereof.

7. A. yarn comprising a core thread containing sufllcient extensibility reducing agent to render the thread relatively inextensible and having permanent grooves and a textile winding embedded therein.

8. The method of manufacturing a fabric 'which consists in incorporating in a normally elastic core thread a quantity of extensibility reducing agent sufllcient to produce a relatively inextensible and plastic thread, embedding a textile winding in said thread to form permanent grooves therein whereby slipping of the textile winding is prevented, incorporating said thread THOMAS LEWIS SHEPHERD. 

